This invention pertains to the art of molding machines and more particularly to a molding machine generally referred to as a vertical flaskless molding machine in which sand received through a vertical hopper is compressed into a desired configuration defining an open top casting cavity. A series of these sand molds are then strung together and advanced along a conveyor for subsequent receipt of molten metal into the cavity at a downstream pouring station.
The invention is particularly applicable to an aerator assembly for use in a vertical molding machine of this type and will be described with particular reference thereto. However, it will be appreciated that the application has broader applications and may be advantageously employed in other related environments and applications.
Known vertical flaskless molding machines, as an example, provide a supply of sand on an inlet conveyor to a hopper where regulated amounts of the sand in the hopper are subsequently introduced into a molding chamber. Clay and other materials that comprise the sand may tend to bind and clump the sand together, a situation that is undesirable where uniform distribution or density of the sand in the mold is desired. In an effort to address binding and clumping of the sand, mold manufacturers supply an aerator assembly that mechanically aerates the supply sand. One commercially available aerator assembly uses a series of paddles, blades, or similar structures situated over the inlet conveyor. The paddles contact the sand as it is transported along the conveyor. The aerator paddles rotate in a fixed direction and at a fixed speed in an attempt to break up the sand before it enters the hopper.
Although widely used, and addressing a portion of the sand binding problems, situating the aerator assembly above the inlet conveyor still does not adequately address introduction of the sand into the mold chamber and the desired goal of uniform density. Various portions of the mold chamber have a greater density of sand than other portions of the chamber. Even though the sand is subsequently pressed to a desired shape, the variation in density can adversely effect the quality of the molded product.
Therefore, even though some aspects of the non-uniform density were addressed by these prior art arrangements, there is no ability to change the displacement and fill rate of the sand into the mold chamber. The fixed direction and speed of the paddles provide minimal aeration.
As with any mechanical device, it is also preferable that any modified aerator assembly be easily serviced and operated. Accordingly, these are still other deficiencies found in the prior art and which have been adequately addressed by the subject invention.